It is thought that strong winds have blown the jellyfish on to the coast
Two more potentially dangerous Portuguese man-of-war jellyfish have been found on the West Sussex coast.
The creatures were washed up on Worthing beaches on Wednesday.
The jellyfish, which usually live in tropical waters and can give a nasty sting, are thought to have been blown on to the coast by strong winds.
Nine Portuguese man-of-war were found on beaches at Bracklesham Bay, East Wittering, West Wittering and Selsey over the weekend.
Bathers swimming or paddling in the sea off Worthing have been urged to be extra vigilant.
Adur and Worthing Councils also urged anyone who was stung to wash the affected area with water and seek immediate medical attention.
Senior foreshore inspector Mac Skeet said: "We don't wont to be alarmist. If you are careful and keep a good look all should be well."
Chichester District Council put up "no bathing" signs following the discovery of nine creatures on their beaches on Saturday and Sunday.
At least 14 Portuguese man-of-war were washed up in Dorset, Devon, Cornwall and the Isle of Wight a week ago.
The Marine Conservation Society has put the "unusually large" numbers of them currently being found along the coast down to recent strong winds.
A Portuguese man-of-war is made up of a colony of creatures to form one jellyfish.
The long tentacles can grow up to 165ft (50m) and hang from a balloon-like float resting on the surface.
Man-of-war colonies are usually found in the Florida Keys and off the Atlantic coast, the Gulf Stream, the Gulf of Mexico, the Indian Ocean and the Caribbean.